Thread cutter for sewing machines



Sept. 18, 1928.

H. L. WILLIS THREAD CUTTER FOR SEWING MACHINES Filed Feb. 11, 1925 Patented Sept. 18, 1928.

UNITED STATES PATENT OFFICE.

HARRY L. WILLIS, OF CHICAGOQILLINOIS, ASSIGNOR TO UNION SPECIAL MACHINE COMPANY, OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS.

THREAD CUTTER FOR SEWIN MACHINES.

Application filed. February The invention relates to new and useful improvements in thread cutters for sewing machines, and. more particularly to a cutter for cutting the enchained loops between stitched articles.

An object of the invention is to provide a chain cutter which is so disposed relative to the stitching mechanism that the enchained loops may be swunginto the thread cutter and the threads cut at the same time when the material is moved laterally to remove it from the'machine.

Another object is to provide a thread cuttor with means for clamping the threads extending between stitched articles prior to the severing of said threads and thus prevent the strain on the threads from springing the. needle or disturbing the stitches or the thread loops so as to cause a shipping of stitches.

Still another object of the invention is to provide the clamping member for clamping the threads with an opening'therethrough arran'gedso that any lint accumulating underneath the clamping member can work up through the opening, and thus permit the clamping member to freely clamp the threadin subsequent cutting operations. I

'These and other objects will in part be obvious and will inpart be hereinafter-more fully disclosed.

In the drawings, which show by way of illustration one embodiment of the invention Figure 1 is a View of a portion of the front end of a sewing machine having the improvements embodied therein; 7

Fig. 2 is a section on the line 2-2 of Fig. 1, showing in dotted lines a stitched article and the manner of swinging the finished stitched article so as to carry the'enchained loops leading from the stitched article to the-stitching elementsinto the thread cutter for clamping the ends of the severedthreads; Fig. 3-is a perspective view of a throat plate and theimproved thread cutter and clamp which is used in connection therewith.

The invention is directed broadly to a thread cutter for severing the threads-101' enchained loops between stitched articles.

' This thread cutter includes a cutting memher and aclamplng member. The cuttlng member 1s so located that the operator, when tween stitched articles.

11, 1925 Serial No. 8,467.

removing a stitched article from the machine, may by actual swinging of the article lay the connecting loops between stitchedv articles against the thread cutter and cut the threads. a clamping member which is located between the thread cutter and the needle for clamping the ends of the threads and holding the same so that the operator in pulling The thread cutter also includes the enchained thread loops against the' thread cutter will not unduly spring the needle. This clamping member is also provided with an opening to allow any lint accumulating under the. clamping member to escape and thus permit theclamping member to firmly clamp the threads.

Referring in detail to the drawings, the

thread cutter is shown as applied to a sewing machine having a cloth plate 11, on which is mounted a throat plate 2. This throat plate is provided with a feed slot 3 in which a feed dog 4 cooperates. This is the ordinary feeding mechanism and fur ther description thereof is not thought elements will. also form 'enchained loops between stitched articles. In ,other words, the machineis capable of chaining off he- The material is held on the work support by means ofa plate is cut away at 9 to forma'recess for the shank 10 supporting the thread clamp and thread cutting member. The throat plate 2 is attached to the cloth plate 11 so as to forma. right angle shoulder 12. The shank'l'O lies in'the recess 9 and'extends along the recess and up over the upper sur- 'presser foot 7 carried by the presser'bar v8. I At one side of the feed slot 3 the throat face of the throat plate 2. Therecess 9 gradually decreases in depth toward the-rear end thereof so as to form a slight clearance for the thread clamping member and, atv the same time, allow the upper surface of the shank 10 to be flush withthe upper surface of the cloth plate at the forward end thereof,

said cloth plate bein likewise raised to the level of the throat plate.

The shank is provided with a thread clamping portion 13 which overlies the throat plate and is adapted to clamp a thread, against the portion of the. throat plate indicated at X in Fig. 3. The extreme rear end of this clamping member is turned up as indicated at 14. One side of the clamping member 13 is turned down as indicated at 15. This down-turned portion 15 lies along the shouldered wall 12 of the throat plate. At the extreme front end of the down turned portion 15 there is a cutting edge 16.

' At the other side of the clamping member 13 from the cutter 16 there is a. projecting finger or arm 17 which extends across the rear end of the feed slot. This finger projects downwardly, as clearly shown in Fig. 3, and will extend into the feed slot in rear of the feed dog. The purpose of this finger is to guide the threadsas they are drawn underneath the member 13 and against the thread cutter 16. The finger also serves to hold the enchained thread loops in a' line opening in the throat plate.

extending directly back from the needle thread loops are passed directly back until the finger is reached, and then will pass over the linger and underneath the thread clamp.

This prevents the pulling on the enchained thread loops when cutting and clamping from being positioned at such an angle to the line of feed'as resultsin a skipping of stitches. It also aids in the proper starting of the stitches in a piece of fabric when a new article is inserted in the machine. The shank 10 which carries the clamping member is, ofcourse, formed of steel-and is bowed slightly, as shownv in Fig. 1, so that the rear end thereof will bear against the upper face of the throat plate.

The enchained loops are indicated at s in the drawings. A stitched article is indicated at S as it passes out of the machine and atS' when the o erator has swung said stitched article to bring the connecting threads or'enchainedloops s underneath the up-turned portionof the clamping member 13. t It will be noted that this thread passes over the finger 17, thence underneath the upturned portion 14, and then against the thread cutter where it is severed by a pull of the operator. The spring of the clam ing member 13 holds the thread so tight y against the throat plategthat a pull of the operator during the cutting of the threads is against the: clamping member and not against-the-needle so as to spring the same.

When the thread is clamped, as above described, the pull of the operator on said thread during the severing of the thread will not disturb the encbained loops formed during the chaining oif, that is stitching one The enchained article to another. Furthermore, the clamping of the thread will hold the thread loops so that, if the needle thread loop is just being formed for the looper to enter, it will not be pulled so as to cause skipping of the stitches. This is very important in chaining to prevent this, the clamping member 13' is provided with a hole 18. in the region of where the ,threadis clamped, and this hole permits the lint to work up through and escape, and thus itis that the clamp is kept free from an accumulation of lint and is always ready to engage and clamp the threads for a cutting operation.

The thread cutting mechanism is located in rear of the needle and at one side of the line of feed, and it is thus disposed so that,

when the operator givesthe stitched article the normal swing for removing it from the machine, the threads extending between the article and the stitching mechanism will be carried into contact with the thread cutter and severed.

It is obvious that minor changes in the details of constructionand the arrangement of the parts may be made without departing from the spirit of the invention in the appended claims.

hat is claimed as new is as set forth 1. The combination with a cloth plate, a

needle, a feed dog and a presser foot, of a combined thread cutter andthread clamp secured to the cloth. plate and located in rear of the presser. foot and at one side of the line of feed whereby when the stitched article is swung on the cloth plate in the usual manner toward the front of: the machine, the stitching threads are drawn-beneath the thread clamp and against the 1 thread cutter for severing the threads. 2. The combination with the needle, 9. feed dog, and a presser foot, of a combined thread cutter and' thread clamping member, including a spring secured to the'cloth plate atone side of the presser footand extending along the same to a point beyond the rear end of the presser foot, said 5 ring member having the rear end thereo turned and having a portion thereof turned down and formed with a cutting edge whereby when the stitched articleisswung on the cloth platein the usual manner toward the front of the machine, the stitching threads may be drawn underneath said upturned end of the spring member and .the thread clamped against the cloth plate by and severed.

3. The combination witha needle, a feed dog and a presser foot, of a thread cutter located in rear of the presser foot and at one side of the line or" feed whereby the stitched article may be swung to position the stitching threads extending from the stitched article to the needle against the cutter for severing the threads, and a thread clamp between the cutter and the needle for clamping the threads before the severing takes place, said thread clamp having a hole formed therethrough adjacent the point where the thread is clamped thereby in order to prevent lint from accumulating therein. I

4. The combination of a needle, a presser foot and a threat plate, said throat plate having a recess formed therein at one side of the presser foot, a metal shank secured to the throat, plate in said recess and extending rearwardly over the upper surface of the throat plate to a point well in rear of said needle, said recess being shaped so as to permit said shank at the rear end thereof to clamp a thread against the throat plate, and a thread cutter mounted on said shank and extending downwardly at right angles thereto so that threads drawn underneath said shank will be brought into contact with said cutter.

5. The combination of a needle, a presser foot and a throat plate, said throat plate having a recess formed th rein at one side of the presser toot, a metal shank secured to the throat plate in said recess and em tending rearwardly over the upper surface of the throat plate, said recess being shaped so as to pern'iit said shank at the rear end thereof to clamp a thread against the throat plate, a thread cutter mounted on said shank and extending downwardly at right angles thereto so that threads drawn underneath said shank will be brought into contact with said cutter, said shank having a projecting finger extending laterally therefrom and into the feed slot at the rear end thereof so as to direct the threads underneath said shank tor the clamping of the threads, said shank having the rear end thereof turned upwardly to aid in guiding the threads underneath the same and having a hole therein adjacent the clamping point for the threads to allow lint to escape.

6. A sewing machine including in combination, a work support, a feeding mechanism, a presser foot, a needle, and a thread cutting and clamping device including a supporting shank having a 'arojecting finger substantially in rear of the needle over which the enchained thread loops may be laid when cutting and clamping, a thread cutting member located in rear of the presser loot and at one side of the line of feed, and a thread clamping member interposed between the finger and the cutter. V

7. A sewing machine including in combination, a worksupport, a feeding mechanism, a presser foot, a needle, and a thread cutting and clamping device including a supporting shank having a projecting finger substantially in rear of the needle over which the enchained thread loops maybe laid when cutting and clamping, a thread cutting member located in rear of the presser foot and at one side of the line of feed, and .a thread clamping member interposed between the finger and the cutter, said thread clamping member having an upturned portion for guiding the enchained thread loops laid across said finger beneath the clamping member, said cutter being disposed below the plane of the clampin memher so that when the enchained thread loops are passed underneath the clamping memher they may be drawn against the cutter.

In testimony whereof, I aflix my signature.

HARRY nwiLtis. 

